There is not any way for you to get the money back from the seller and Ebay will not get involved with this.
You can mark the seller down for postage costs in their star ratings and leave feedback to express your issue.
However, that will not get your money back unfortunately.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)